Apparatus for classification and separation of material particles



p 3. 1940..-- E. 1.. WIEGAND 2,213,510

APPARATUS FOR CLASSIFICATION AND SEPARATICYN OF MATERIAL PARTICLES 11ndJune 23; 1937 10 Sheets-sheaf].

l 1.9; a 2004/ if] EdwinL.We and,

ATTORNLYS 1*- 3 1940! V E. L. WIEGAND 2,213,510

APPARATUS FOR CLASSIFICATION AND SEPARATION OF MATERIAL PARTICLES FiledJune 23, 19s"; 10 sheets sheet 2 IN VLNTOK wawwmw p 3, 1940- .E. WIEGAND2,213,510

APPARATUS FOR cmssmcnxon AND SEPARATION OF MATERIAL mums 4 Filed June23, 19s? 10 Sheets-Sheet s lNvzu-roK Edwin. L-We9axid 1 1 flaw, MM M 10Sheets-Sheet 4 E. WIEGAND Filed June 23,195?

APPARATUS FOR CLASSIFICATION AND SEPARATION OF MATERIAL PARTICLE Sept.3. 1940.

Edwin. Lwiegancl INVNTOK ATTORNEJS Sept. 3, 1940. E. WIEGAND 2,213,510

APPARATUS FOR CLASSIFICATION AND SEPARATION OF MATERIAL PARTICLES 7Filed June 23, 1937 10 Sheets-Sheet 5 Edwin. Lwioscund LNvwToR 1 Sept.3. 1 I E. WIEGAND APPARATUS FOR CLASSIFICATION AND SEPARATION OFMATERIAL PARTICLES Fi1ad Jun e-23, 1937 10 Sheets-Sheet 6 zgand.

p 3, 1940- E. 1.. WIEGAND 2,213,510

APPARATUS FOR CLASSIFICATION AND SEPARATION OF MATERIAL QPARTI CLESFiled June 23-, 19:57 10 Sheet=heet 7 0E} {N F N w 12:33: E f fmjwzm mAT TO \zwrqs p 1940 E. L. WIEGAND 2,213,510

'AIPARATUS FOR CLASSIFICATIfiN AND SEPARATION OF MATERIAL PARTICLESFiled June 23, 1957 10 Sheets-Sheet 8 1Z1 Edwin. L-Wzganc1 Sept. 3,1940. E. L. WIEGAND 2,213,510

AFPARA'IUS FOR CLASSIFICATION AND SEPARATION OF MATERIAL PARTICLES FiledJune 23, 1937 10 Sheets-Sheet 9 V H in"'IlWWII/IIIIIIIIIIIIIIIIIIIIIIIIIIIIII/fl Edwin, L.Wi5anoL INVENTOK 31M. MM Z/W ATTQRRLETS Sept 3, 1940- v I E. L; WIEGAND 4 2,213,510

APPARATUS FOR CLASSIFICATION AND SEPARATION 0? MATERIAL PARTICLES FiledJune 23, 1957 1o Sheets-Sheet 1o ROLLONE CHUTE one ROI. Two d-IuTETWOfl4--( 4 (5 2%G=E3F=:"Z

. Edwin. L W.5anc\ INVS-NTOR l I AT o RN-EYS Patented Sept. 3, 1 940UNITED ZS'I'TATES PATENT OFFICE APPARATUS FOR CLASSIFICATION ANDSEPARATION OF MATERIAL PARTICLES Edwin L. Wiegand, Pittsburgh, Pa.Application June 23, 1937, Serial No. 149,806 16 Claiins. (or. 209-127)My invention relates to electrostatic classification and separation ofmaterial particles, and more particularly to new and improved apparatusforcarrying out the processes of thermoelectrostatic separation ofparticles as described and claimed in myco-pending application SerialNumber 755,694, and the principal object of my invention is to provide anew and improved process of electrostatic separation and moreparticularly to provide new, and improved appa.

ratus for electrostatic separation in general and in particular forthermo-electrostatic separation.

In the drawings accompanying this specificastructure shown in Figure 1,certain parts being omitted and other partsbeing broken away,

Figure 3 is an enlarged fragmentary side elevational view,

Figure 4 'is a fragmentary vertical sectional view, illustrating thehopper feed to the first unit of the apparatus,

Figure 5 is a fragmentary vertical transverse sectionalview,ilITstrating two intermediate rolls and cooperating'parts,

Figure 6 is a fragmentary vertical transverse sectional viewillustrating the lowermost roll of the machine and the immediatelyassociated .parts,

Figure 7 is a broken sectional view taken on the line 1-1 of Figure 5,looking in the direction of the arrows, certain parts being omitted forthe sake of clearness,

-Figure"=8 is a fragmentary side elevational Figure 9 is a broken planview .of the chute shown in Figure 8, parts being broken away to viewthrough a roll, and drawn to a reduced size, showing the heating elementdisposed within the roll,

Figure 13 is a diagrammatic view illustrating the construction of theresistor within the heat- 5 being shown in section, and parts beingdiagrammatically show-n, of a control board, and

Figure 15 is a diagrammatic view showing an 10 electrical controlcircuit which may be used with the embodiment of my invention.

Referring to the drawings and to the apparatus as a whole, the apparatushere shown is particularly adapted for the purpose of. suc- 15 cessivelypassing the particles to be treated through a plurality of treatingzones and accordingly there are shown, in this instance, four treating.units 20, 2|, 22, 23, each disposed at a lower. level than thepreceding unit. Each unit 20 includes a roll,.each roll being designatedprimarily by the reference numeral 24 and the respective rolls beingdesignated 24a, 24b, 24c, 24d. Each unit also includes an electrode 25(see Figures 4 and 5, for example), anda chute 26. 25

-The euppermost chute 26 (designated 26a) is adapted to receiveparticles thereon, from hopper means 21, and deliver them to the roll.26a. The chutes 26b, 26c, 26d are adapted to respectively receive aportion of the particles coming 30 from the roll immediately above anddeliver them to the roll immediately below. A portion of the particlescoming from the lowermost roll 24d, fall into a chute 28. Thus a portionof the material delivered to the chute 26a passes 35 through all of thetreating zones and finally reaches the chute 28. Other portions of thematerial are successively separated out, all as will fully appearhereinafter.

The units 20, 2], 22, 23 are shown as supported 40 on a frame comprisingspaced supporting members 29, 30, such as angle bars, inclined aboutthirty degrees with respect to the vertical, these supporting membersbeing carried by spaced upright angle bars 3|, 32 extending fromsubstan- 45 tiaily the upper extremity of the inclined supports 29, 30to the fioo-r level, and by spaced angle bars 33, 34 extending fromsubstantially the lower extremity of the inclined supports 29, 30 to thefloor'level. The inclined supports 29, 30 50 and the upright supports3!, 32,'33,' 34 are braced in any suitablemanner, as by bracing bars,some of which, as 31, 38 are visible in Figure 1.

Each of the rolls 24 extends transversely across 55 the inclinedsupports 29, 30, and near the end of each roll is a roller bearing 39,best shown in Figure 11. The rolls 24 have reduced extremities 40 andeach bearing 39 is adapted to receive and journal one of the reducedextremities 40. The bearings 39 at one side of the apparatus aresupported by the inclined support 29 and those at the other side of theapparatus by the inclined support 39.

That part of the roll, of largest diameter,'between the reducedextremities 40, for the sake of brevity will be referred to as theactive part.

The bearings 39 are fastened to the respective inclined supports 29, 39as by studs 4|. Each bearing 39 is preferably covered by a sheet metalhousing 42. To efliciently protect the bearing against the entrance ofparticles, a split ring 43 having flanges 44, 45 providing an annulargroove is secured to the reduced extremity of the roll at the side ofthe bearing nearest thte active part of the roll, and an end wall 46 ofthe housing 42 is provided with a slot 41 so constructed and arrangedthat the side wall 46 cooperates with the groove provided by the flanges44, to prevent the entrance" of particles into the bearing. The otherend wall, 48, of the housing 42 is also provided with a slot, 49,slidably fitting the reduced end 40 of the roll. By reason of the slots41, 49 the housing 42 may be readily assembled with the bearing andassociated parts, and may be fastened in place in any suitable manner,as by metal strips 50 fastened by screws to the housing and to the blockor pedestalof the bearing 39, as best seen in Figure 3.

Each roll 24 is tubular and disposed within each roll is an electricheating element 5|, as may be seen best in Figure 12. The heatingelement 5| is preferably of the cartridge type, and comprises an outersheet metal sheath 52 closely and slidably fitting the inside diameterof the roll 24, and containing a'resistor 53 here shown as a helicalresistance wire wound upon a refractory form 54. Suitable refractorymaterial 55 is disposed within the sheath to space and electricallyinsulate the resistor from the sheath.

As indicated in Figure 1.3, the resistance wire is desirably woundcloser together at the extremities of the heating element 5| than at theintermediate portion, so as to more evenly distribute the heatthroughout the roll by compensating for heat loss along the extremitiesof the roll.

The respective ends of the heating element 5| are provided withterminals 56, to each of which is clamped a metallic corrugated strip51, preferably of Monel. metal. To the free end of each sheet metalstrip 51 is secured a rather heavy piece of Monel wire 58, this wirepassing through'an aperture 59 in a block or disk 60, desirably formedof lava. The wire 58 has its end bent over to lie in a recess 6| formedin an end surface of the insulating block 60. The insulating block 60 issecured to the extremity of the reduced end 40 of the roll- 24 by meansof contactmeans 66 is provided for carrying current to the contact disk64, and it will of course be understood that a similar contact means isprovided at the other end of the roll 24.

The contact means 66 comprises a screw 61 having a conical end 68adapted to engage in a complementary conical recess 69 in the metal disk64. The screw 61 is in threaded engagement with an internally threadedsleeve 10 and may be held in fixed relation with the sleeve 10, afterany desired adjustment, by means of alock nut 1|. The sleeve 16 iscarried by a resilient arm 12 which has an aperture (not shown) throughwhich the sleeve is disposed, the sleeve being insulated from the arm bya suitable insulating sleeve (not shown) and washers 14. One end of thesleeve 10 has a flange 13 bearing against the adjacent insulating washer14 interposed between it and the arm 12. The other end of the sleeve 10is externally threaded and carries a nut 15, bearing against the otherinsulating Washer 14, for fastening the sleeve to the arm. A nut 16serves to clamp a conductor 11 against the nut 15.

The arm 12 is fastened at its lower end to a rod 18 in turn fastened tothe adjacent support member 39. It will be evident that by adjusting thescrew 61, the pressure applied by the resilient arms 12 to press thescrew point 68 into the recess 69 may be varied and that the screw point68 and the disk 64 provide a slip connection permitting rotation of theroll 24.

The arm 12 may also carry a cup-shaped sheet metal housing 19 forenclosing the contact means 66, and may at least partially surround theinsulatingdisk 69. The conductor 11 may be led through an insulatingbushing 80 (see Figure 3) carried in the housing 19, to a source ofcurrent, and the conductor 11 at the other end of the roll maybesimilarly so led, thereby to supply heating current to'the resistor 53.

Each of the rolls 24 in the illustrated embodiment 'of the invention isconstructed and arranged as hereinbefore described and is provided withcontact means for supplying current to its heating element asdescribed.

The electrodes 25 of each of the units 29, 2|, 22, 23 are identical, asare also the respective means for supporting these electrodes andaccordingly. reference will be had to the electrode 25b' of the unit 2|shown best in Figures 3, 5, and 7.

The electrode 25b is spaced from the roll 24b, and extends parallel tothe roll 24b, approximately the active part of the roll. The electrodeis adjustable to any desired position with respect to the roll, as willappear.

The adjustable supporting means for the electrode 25b includes arms 8|,82-respectively secured at their lower ends to the supporting members29, 30 adjacent the bearings 39. Each arm BI, 82 has an open slot 83, atits upper end, forming a bearing surface. The slots 83 serve to journalthe reduced ends -of a bar '86, which may be rotatably adjusted in theslots 83 and then held against rotation by means of machine bolts 81screw-threaded into the'extremities of the bar 66 and bearing againstwashers 88 in turn bearing against the adjacent surface of therespective arms 8|, 82. The bar 66 is provided with spaced apertures 89to slidably receive one end of a pair of similar angle rods 90. Theother end of each angle rod 90 slidably supports a block 9|. The blocks9| have apertures serving to journal the reduced ends of a second bar,92,

and the bar 92 may be held against rotation in adjusted position bymeans of machine bolts 93 in a manner similar to that described inconnection with the bar 86. Insulating members 94 are suitably carriedby the second bar, 92, as by means of machine bolts 95, and theelectrode 251) is carried by the spaced insulating members 94, in anysuitable manner, as by studs 95.

It will be evident that the electrode 25b may be swungabout the aXis ofthe rod 06 and held in position by the machine bolts 81. Further, thatthe electrode 25b may be adjusted in a generally horizontal direction bysliding the upper ends of the angle rods 90 through the apertures in therod 06. Set screws 91 serve to hold the angle rods in the adjustedposition. Further, that the electrode 25b may be adjusted in a generallyvertical direction by sliding the blocks 9| on the angle rods 90. Setscrews 90 serve to hold the blocks 9| in adjusted position.

Under the influence of the electrode 25b, different particles describedifferent trajectories in coming from the roll 2411, as indicated by thedotted lines in Figure 5. The electrode is of a cross-sectional outlinethat may be described as of elongated ovoid shape and is moreoverdesirably convex onits upper side and concave on its lower side so as toconform approximately to the trajectories of the particles in itsneighborhood.

To divide the particles so that some proceed to one place and others toanother place, adjustable dividing means, here shown as a divider bar 99of generally triangular cross-section, is provided. The divider bar 99is disposed parallel to the roll 24b and the triangular portion of it issomewhat longer than the active part of the roll.

The divider bar 99 is provided with cylindrical ends I adapted to bereceived in journal slots IOI in the lower sides of the arms 8|, 82, sothat 1 the divider bar is pivotally mounted for movement about itslongitudinal axis, within limits. Within these limits the apex of thebar 99 is directed generally toward the stream of particles coming fromthe roll 24b. 1

One extremity of the divider bar 99 is extended beyond the arm 82, is ofreduced cross-section and has keyed thereto an adjusting plate I03, (seeFigures 3 and 7) formed with an integral handle I04. The adjusting plateI03 is provided with an arcuate slot I05, and disposed within the slotis a machine screw I06 threaded into an aperture formed in the arm 82,so that the adjusting plate may be clamped against movement. Theadjusting plate is also provided with a pointer I0'I cooperating with ascale I08 carried by the arm 02'. It will be obvious that the dividerbar 99 may be swung to a desired position by the handle I04, and held inthe desired position by tightening the machine screw I06. The dividerbar 99 carries plates I09, H0 at the extremities of its triangularportion, these plates being suitably fastened to the left hand face ofthe divider bar, as viewed in Figure 5.

The construction and arrangement of the divider bars is the same in allof the units 20, 2|, 22, and 23.

Each unit 20, 2|, 22, 23 comprises a receptacle or housing structure I II, serving to receive a portion of the particles coming from eachrespective roll, and serving also other purposes as will appear. As thereceptacles III are all identical they maybe described by reference toFigures. 3, and '7. The receptacle III has side plates or walls H2, 3,which are so spaced as to slightly clear the end plates I09, I I0on thedivider bar 99.

g to the electrode 25 in any suitable manner.

The receptacle III further includes a wall II4 which serves as a top,front, and bottom wall for the receptacle. The bottom wall is curved,ex-

tends upwardly, and terminates at H6 in a recess I I5 in the base of thedivider bar 99.

The side walls H2, H3 areeach provided with recesses II8, II9 toaccommodate the rod 86 and the ends I00 of the divider bar.

The bottom wall of the receptacle III has suitably fastened theretolaterally and downwardly extending brackets I20, I2I. The lower ends of"the brackets I20, I2l are bent so as to rest flat on the supportmembers 29, 30 respectively, and the bent ends are bifurcated, toreceive, between the respective furcations, pins. I22 secured to therespective supporting members 29, 30. The pins I22 are transverselyapertured, to receive securing pins I23.

The side wall II3 of the receptacle is apertured and this aperture"communicates with an outwardly extending pocket I 24, open at its upperend. The lower end of the pocket I24 has a con- Disposed in the bottomof each receptacle III is a disk-like rake I34, which is secured to arod I extending through the side of the pocket I24, and the outerextremity of the rod I35 isprovided with a handle I36, so that materialwhich has accumulated at the bottom of the receptacle may be removed bypulling outwardly on the handle I36 so as to cause the rake to scrapethe material toward and into the pocket I24 and thence into therespective conduit I25, and in the case of the unit 23, into the conduitI32. It will be appreciated that other means may be provided for thepurpose of removing material from the receptacle III, such as anautomatically regulated conveyor screw arrangement.

The front wall of the receptacle III of each unit 20, 2I, 22, 23,carries a high potential insulating bushing I31, bestseen in Figure 5.The insulating bushing I31 may have a conducting socket at each end, thesockets being connected 'by a conductor I43 (see Figure 7) The socket atthe lower end of the bushing may have plugged thereinto a plug terminalon a conductor I38, which may be fixedly connected at the other end Thesocket at the outer end of the bushing I31 may have plugged thereinto aplug terminal on a conductor I39. The conductors I39 of the differentunits are here shown as fed from a high potential bus I40 suitablysupported on high potential insulators.

The bus I40 may be connected to the positive terminal of a source ofelectricity (not shown) providing variable unidirectional highpotential, the other terminal being. connected to the frame of theapparatus or to ground. With my invention potentials as low as 1,000volts may receptacle III is also provided on its front wall with a pairof handles I42.

It will be apparent that the receptacles III each may be readily removedby withdrawing the pins I23, disconnecting the conductor I38 from thesocket in the bushing I31, and pulling upwardly on the handles I42 toremove the end of the conduit I from the conduit I26, and swinging thereceptacle about the bar 86 until the recess I I8 and the bar 66 may bedisengaged.

Each receptacle III serves to shield its associated electrode 25 andelectrostatic treating zone from drafts, foreign electrical charges andother extraneous undesirable influences or interferences.

The chutes 26b, 26c, and 26d are identical and accordingly a description.of the chute 260, shown best in Figures 5, 8, 9, and 10, will serve forall.

The chute 26c comprises a. platter-like frame I44, having upstandingside walls I45 and upstanding end walls I46, I56, as best seen in Figure9. Extending across the chute between the side walls I45 is a partitionor barrier I41 having a plurality of apertures I48, desirablydistributed along the entire length of the barrier. The barrier I41divides the chute into a receiving portion I49, disposed to receive someof the particles coming from. the roll 24b, and what may be termed aconveying portion I50. The lower end wall, I56, of the frame is providedwith a plurality of spaced apertures I5I, desirably distributed alongthe entire length of the wall I56, and extending downwardly at a steeperangle than the surface of the portion I50, and opening at their lowerends into what may be termed the discharge portion of the chute. Thedischarge portion includes a nose piece I52 having a recti-' aperturesI55, desirably distributed along the entire length of the wall I54, atthe surface of the bottom wall I53. The trough I51 is provided with endwalls I65 to'prevent the particles from flowing endwise from the trough.The end walls I65 are spaced apart a distance somewhat less than thatpart of the roll 240 having the largest diameter. It will be noted thatthe trough I51, and the nose piece I52 are somewhat longer than thewidth of the portion I50 of the chute to pre-- vent excess accumulationvof particles at the end portions of the trough. The trough I51 may befastened to the nose piece I52 by screws I58 and be adjustable towardand away from the free margin of the nose piece.

To control the flow of particles immediately before they reach theapertures I55, a swingable' gate I59 is provided. The gate I59 has armspivoted at I60 to opposite side walls I45 of the frame member I44, andhas a generally V-shaped end I6I extending into the collecting troughI51. The gate I59 is biased by its.own weight to the position shown inthe drawings and the apex of the V-shaped end rests on the bottom wallI53. The apex of the V-shaped end of the gate is profurther flow of theparticles onto the roll.

vided with small notches I 62 to permit passage of the particles.

As best shown in Figure 10, one edge of the gate I59 is slotted toreceive an elongated heating element I63 of the strip type, this heating5 element being secured in position by meansof screw bolts I64 which areadapted to compress the walls of the slot against the sides of the heatjing element.

A sheet metal strip I66 maybe secured to the '10 wall I56 of the frame,so as to have its lower margin partially obstructingjhe inclined aper-ltures I5I, tolevel out the flow of particles coming; out of theseapertures.

As shown in Figure 10 the nose piece I52 and'l5 the discharge trough I51are so related to the roll Y 240 that, should the roll cease revolving,the particles will form a mound on the roll sealing the aperturesl55 inthe trough I51, and stopping How 20 flow of particles is stoppedelsewhere in the apparatus under abnormal conditions will be set forthhereinafter.

For supporting the upper end of the frame I44, opposite sides of theframe are provided with 25 laterally extending arms I61, each having ascrew-threaded aperture for receiving a screwthreaded stud I68, the studbearing against the adjacent surface of a respective inclined supportingmember 29, 30. For supporting the 30 lower end of the frame I44, lugsI69 are provided, these lugs being spaced from the arms I61,longitudinally of the frame I44, and extending laterally, but not farenough to cross the support members 29, 30.

For cooperation with the lugs I69, there are mounted on the insidelateral walls of the supporting members 29, 30, brackets I10, eachhaving a seat surface I1I in the general plane of the frame I44 andadapted to be engaged by screw- 40 threaded studs I12 extending throughthe respective lugs I69. Each bracket I10 also has a transverse wall I13through each of which extends a screw-threaded stud I14, each adapted toengage a respective transverse abutment surface of the lugs I69. Flatspring arms I15 are carried by the lateral sides of supporting members29, 30, one end of each spring arm being secured to a respectivesupporting member, as by a machine screw I16, and the other end of thespring arm bearing against a longitudinally extending surface of arespective lug I69. An adjusting screw I11 is threaded through therespective supporting members 29, 30, each bearing against anintermediate portion of the respective spring arm I15 to adjust thespring pressure bearing against the lug surface.

It will be obvious that the frame I44 may be adjusted toward and awayfrom the roll 240 by adjustment of the screws I14. If desired, lat- 60eral adjustment may be secured by adjustment of thscrews I11. Therelation of the margin of the nose piece I52 with respect to the roll240 may also be adjusted by the screws I12. The

angle of the frame I44 with respect to the horizontal may be adjusted bythe screws I68 or by the screws I12 or by both. The angle of the chutewith respect to the horizontal is desirably so adjusted that the angleis a predetermined amount greater than the angle of repose of the 70particles being treated, resulting in slow descent of the particles.

The conveying surface I50 of the frame I44 is covered by a sheet metalplate I18 (see Figure 5). The plate' I18 extends upwardly slightly overthe barrier I41 and has a portion II9 extending.

cessed, to provide space for a plurality of heating'elements I82,preferably of the strip type,

these elements being secured to the under-surface of the frame by meansof a desired number of spanning plates I83, and bolts I84, I85. On thebolts I84 areprovided spacer washers I86 which bear against a baflieplate I81 which in turnv bears against nuts I88 holding the spanningplate I83, and is thus held spaced from the spanning plate. The bafileI81 desirably has a highly polished surface so as to reflect the heattoward the under-surface of the frame I44. Heat insulating material I89may be disposed between the baflle plate I8! and a dished sheet metalplate forming a cover I90 for the undersurface of the frame I44. Thecover I90 cooperates with a housing I9I to house insulated bus bars I92to which the terminals of the strip heaters- I82 are respectivelyconnected. Terminal studs I94 are connected to the bus bars I92, andconductors I95. connected to the terminal studs I94 lead to a source ofcurrent. A junction box I96 supported by the housing I9I may be providedfor the terminal studs I95.

Each roll has cooperating therewithmeans for removing therefromparticlesthat adhere thereto after those particles have passed out ofthe range of the electrostatic field provided by the respectiveelectrodes 25. To that end each roll has cooperating therewith a brush,in the case of the roll 241) the brush I9Ib, extending along the activelength of-the roll 24b. The brush, I9'Ib, is carried by a rod I98 inturn suitably carried by the supports 29, 30.

A sheet metal auxiliary or, back chute I99b is disposed, generally atright angles to the chute structure 260 and in such position thatparticles brushed from the roll 241) are adapted to fall into it andthence slide to a bin 200D (see Figure 1). These particles may be termedthe backs. I The units 20, 22, 23 are similarly provided with backchutes I99a, I990, I99d leading to bins 200a, 2006, 200d respectively.

Each back chute has a flange 20I extending.

downwardly from the entrance edge of the chute, and is adjustablymounted for movement transversely with respect to the axis of therespective roll. To the latter end brackets, one of which 202, may beseen in Figure 5, are suitably secured to the flange 20I at oppositesides of the back chute, these brackets having elongated slots date thecylindrical ends- I of the divider bar 99. These plates 205 serve asdownward continuations of portions of the walls I I2, I I3 of thereceptacle III.

Means is provided for measuring the temperature of the heads, here shownas including an elongated tube 206, containing thermally respon siveexpansible fluid, supported by angular brackets one of which, 201, maybe seen in Figures and 9, suitably fastened to the receiving surface I49of the frame I44. The brackets also carry a collecting trough 208,surrounding the tube, and open at the top and bottom, so that at least aportion of the heads will be collected in the trough and pass inproximity to the thermally responsive tube, and out of the open bottomof the trough structure.

Another tube, 209, similar to the tube 206, is disposed adjacent thelower end of the conveying portion I50 of the frame I44, and issupported at its ends by angular brackets one of which, 2I0, may be seenin Figures 5 and 9. The tube 209 is so supported that its underside isclose to the surface I50 but leavingsufilcient space for the stream ofparticles to flow under the tube. As indicated in Figure 9, thethermally responsive tubes 206,- 209 need not extend fully across theframe I44, satisfactory results being obtained when the tubes extendfrom one side to substantially the middle of the chute surfaces of theframe, or otherwise partway across these surfaces.

The thermally responsive tubes are provided with conduits 2I I, 2I2leading outwardly of the chute structure to indicating instruments aswill further appear.

The uppermost chute structure, 260:. (shown in detail in Figure 4) isadapted to be fed by a plurality of pipes 2I3 leading from an open topdish-shaped receptacle 2I4. The pipes 2I3 have branches 2I5 (see Figure2) so as to more evenly distribute particles to the receiving portionI49.

The receptacle 2I4 is carried by a hopper2I6,

by means of straps 2II, andthe hopper is in turn carried by the spacedsupporting members 29, 30, by means of a circular tubular band 2!secured to the 'hopper. The band 2!!! is secured to braces 2I9 which arein turn secured to the supporting members 29: 30. As best shown inFigure 4, the hopper 2I8 is of inverted cone shape, the large open endsupporting a plate-like member 220 having an open bottom, a screen 22Ibeing secured in spanning relation with respect to the open bottom. Theplate-like member 220 is merely hungwithin thehoppcr, its rim resting onthe upper rim of the hopper, and is readily removable. A cover 222 isprovided to close the plate-like member 220 and the hopper.

Material may be conducted to the hopper by means of a conveyer 223(Figure 1), such as a belt conveyer carrying scoop buckets, the scoopbuckets emptying into a conduit 224 at the upper end of the conveyer,and the conduit discharging into the hopper 2 I6. The cover 222 of thehopper may be apertured to provide for the conduit 224, or the cover 222may be removed if desired. As best shown in Figure 1 the hopper 2 I I5is desirably provided with a low-level responsive device 225 of anysuitable form, and the conduit 224 is desirably provided with ahigh-level responsive device 226, these level responsive devices beingresponsive to the minimum and maximum levels of the material in thehopper, and operate to control the conveyer 223 as will appear.

In Figure 15 is shown an electrical system WhlCh able by the minimumlevel'control device 225.

may be employed with the level responsive devices 224, 225. This systemcomprises a switch 221; which is operable by the maximum level controldevice 226, and a switch 228 which is oper- A motor229 for operating theconveyer 223 may be fed from the line 238, through a manual switch 23land through a contact 232 of an electromagnetically operated contactorhaving an operating coil 233. The operating coil is connectable in shuntwith the line 238 through a holding contact 234 operable by thecontactor, and through the level responsiveswitch 2,21. The levelresponsive switch 228 is connectable in shunt with the holding contact234. Assuming that the manual switch 23! is closed, and also-that thehopper M6 is entirely empty, the switches 221, 228 will be closed by therespective levelr'esponsive devices causing energization of the 0011 233of the contactor and closure of the contacts 232, 234. Closure ofcontact 232" completes the circuit through the conveyer motor 229,starting the feed to the hopper 2 l6. when the level in the hopper risesto the level responsive device 225, the latter opens the switch 223 butthe contactor is maintained closed by the coil 233 because the holdingcontact 234 is held closed. When the maximum level is reached, themaximum level control device 226 opens the switch 221, which causesdeenergization of the contactor coil 233, and the contactoris caused toopen by reason of a spring or gravity, simultaneously opening thecontacts 232, 234, thus breaking the circuit through the conveyer motor229 and stopping the feed to the hopper. When the material again dropsto the minimum level, the switch 228 closes, and the previouslydescribed cycle is repeated.

The uppermost chute structure 26a, not having any roll above it, servesonly to feed particles from the hopper means 21 to roll 24a below it,but is otherwise constructed and arranged as already described inconnection with the chute structures 26 (b to d).

Disposed below the lowermost roll, 2401, is the delivery chute 28, forreceiving the heads from the unit 23; the upper end of the chute 28 runsthe active length of the roll 24d, tapers to a smaller size at its lowerend and leads into a hopper 236 at the base of a conveyer 231 adapted totake material from the hopper 236 and convey it to a desired place. Thedelivery chute 28 is suitably secured to the spaced supporting members29, 38 as best shown in Figure 6. I

The lowermost roll, 24d, is rotatable by a sheave 238 driven by beltsfrom a motor (not shown). The roll' 24d also has secured thereto asmaller sheave 239 adapted to drive a sheave 248 secured to the roll 24cthrough belts 24l. The sheave 248 is here shown as adapted to carrybelts 242 for driving a sheave 243 secured to the roll 24b, and in likemanner the sheave 243 carries a belt 244 for driving a sheave 245secured to the roll 24a. It will accordingly be apparent that eachrollserves as a transmitting means for transmitting power to drive all ofthe rolls which are at a higher level. Thus, for example, if the belts242 should break, rolls 24c, and 24d would continue to rotate but rolls24a. and 24b would stop. Or, if the belts 242 should slip, the roll 24aas well as the roll 24b would be driven more slowly.

Each of the rolls is driven in the direction indicated by the arrows(see for example Figure 5) and is preferably driven at a speed such thatthe effect of centrifugal force on the particles is substantiallyabsent.

'The'heating of the rolls :4 (a to d) and the chutes 26 (a to d) may becontrolled by the control apparatus shown in Figure 14, comprising aplurality of panel boards. There are desirably at least as many pairs ofpanel boards as there are treating units 28, 2|, 22, 23. A descriptionof one panels. A pair of conductors 248 lead from the panel 246 to theheating element 5| of the roll 24a. These conductors 248 may be the sameas or an electrical continuation of the conductors 11 in Figure 11. Theconductors 248 may be supplied with current from a bus 249 and any oneof a plurality of buses 258, the bus 249 leading to one terminal of atransformer (not shown) and the buses 258 leading to taps on thetransformer. A selector switch 25| is provided for selecting the desiredtransformer tap bus. Interposed between the selector switch 25| and theconductors 248 is a manually operable switch 252, normally closed whenthe apparatus is in operation, and a contactor 253 having an operatingcoil 254. The contactor is here shown as of a type which opensitscontacts when the coil 254 is energized, the contacts being normallyheld in closed position by a spring 255, or by gravity, art willunderstand that, if desired, the contactor may be of the type in whichthe operating coil closes the contactor and a spring or gravity biasesit to open position.

The coil 254 of the contactor is adapted to be energized from a pair ofbus conductors 256 leading to a source of current (not shown), andenergization of the coil 254 is controlled by temperature indicatinginstrument 251 the movable element of which is adapted to close a switchhaving a relatively stationary contact 258, the switch being interposedin the circuitbf the coil 25.4 and operable when a predeterminedtemperature is reached. The contact 258 may be adjusted to anypredetermined temperature as; indicated by a pointer 259.

The movable element of the temperature indicator 251 is actuated by theexpansible fluid in the thermally responsive device 286 disposed in thepath of the heads coming from the roll 24a, by means of a tube 268leading to the device 286. When the temperature of these heads rises toa predetermined value the temperature indicator causes energization ofthe coil 254 thus interrupting the circuit of the heating element 5| ofthe roll 24a. When the temperature of the heads is below thepredetermined value the contactor 253 remains closed.

The supply of current to the heating element 5| may be interrupted atany time by the switch 252 and also set at a selected value by theselector switch 25L The construction and operation of the panel 241 isidentical with that of thepanel 246 except that a temperature indicator26L corresponding to the indicator 251, has a tube 262 leading .to thethermally responsive device 289 on the chute 26a, and conductors 263lead to the strip heaters I82 for heating the chute 26a. Thus theapparatus in the panel 241 controls the current to thestrip heaters I82of the chute 26a in a manner similar to that already described withrespect to the control of the heating of roll 240. by the apparatus onthe panel 246.

The respective heating elements I63 of the respective gates- I55 mayalso be controlled in a manner'similar to that described, and may becontrolled by the same control which regulates pair of panels, 246, 241,will suffice for all of the Those skilled in the I static field 'notonly in the unit 20 but in all of tails, the heads, and the backs may bevaried by the operation of the heating element within the respectiveadjacent rolls.

If desired, an indicator light 264 may be mounted on each panel, and maybe so connected that it will indicate whether the heaters connected tothat panel are energized or not.

Safety fuses 265 may be interposed in the supply lines.

In the operation of the machine, material from the hopper 2 I6 isdelivered to thedish-shaped receptacle 2M, from where it passes throughthe pipes 2I3 and is distributed over the receiving surface I49 of thechute 26a. The material then gravitates through the apertures I48 in thebarrier I I'I onto the conveying surface I50 down that surface andthrough the inclined apertures I5I into the trough I51. In the troughI5'I the particles must' fiow through the notches I62 in the gate I59and thence through the fine apertures I in the wall of the trough I51,onto the roll 24a. It will be evident that the construction andarrangement of the chute structure is such that by the time theparticles reach the roll they will be evenly distributed onto the rolland will fall thereon in a very thin stream so that as the roll rotates,it will carry only a very thin film of particles. Meanwhile theparticles have been heated by the strip heaters I82 and I63, and thefilm of particles on the roll is either further heated to a highertemperature or maintained heated by the heater 5I in the roll.

The temperature to which the particles are heated will depend on thenature of the particles,

in accordance'with the process disclosed-in my co-pending applicationSerial Number 755,694.

As the roll 24a rotates it brings the film of particles thereon into therange of influence of the positively electrically charged electrode250..

the succeeding units.

By reason of the heated condition of the particles the motion responseof particles of different nature is different and consequently the speedand trajectories of a portion of the particles will be such that theywill fall to' the left of the divider 99, as viewed in Figure 5; theseparticles, the tails, accumulate in the receptacle III. Another portionof the particles, which have a smaller motion response to theelectrostatic field, fall between the divider 99 and the flange 2M;these are the'heads. Another portion of the particles either falls offof the roll to the right of the flange 2M, into the back chute I991), oradheres to the roll and is brushed off, by the brush I9'Ib, into theauxiliary chute I99b; these particles are the backs.

It will be evident, in view of the construction and arrangement of theelectrode 25b, that mechanical deflection by the electrode of particlescoming towards the electrode from the roll 24b, is minimized, while atthe same time undesirable intensity of field as between the electrodeand, for example, the divider 39 is avoided.

It will be evident that for a given temperature of the particles and agiven potential on the electrode, the relative proportions as betweenthe adjustment of the divider 99 or by adjustment of the flange 29I orby adjustment of electrode or by any combination of these adjustments.

Thus, the heads from any one of the rolls fall 'onto the next succeedingchute, as for example,

the heads from the roll 24a of the unit 20 fall onto the chute 26b. Inthe unit 2I the heads coming from the unit roll 24b are further dividedinto tails, heads, and backs as hereinbefore described, and so onthrough the lowermostunit 23 from which the final heads pass into theunheated chute 28.

When the apparatus is used for the production of refractory materialsuitable'for example for refractory electrical insulating material, theheads are the final desired product. However, any one or all of theheads, the tails or the backs may constitute valuable products. 7

It will of course be evident that any onefof the portions of theseparated particles may be. again run through the apparatus for afurther separation.

As pointed out in my co-pending application Serial Number 755,694,successive treatments of the material may be at different temperatures,that is, the temperature of the particles while in the field of theelectrode 250. may be a selected temperature and the temperature of theparticles while in the field of the electrode 25b may be at a differentselected temperature, either higher or lower than the first namedtemperature, and so on through the successive units.

The construction and arrangement of the apparatus is such that shouldone of the rolls stop rotating, the flow of particles will beautomatically stopped thus preventing an accumulation in undesiredplaces of untreated particles mixed with previously treated particles.For example, referring to Figure 5, should the roll 241) stop (whereuponthe roll 24a also stops) the particles will form a mound on the roll 24bpreventing fu'rther'fiow of particles out of the apertures I55. Anyparticles descending on the chute will form a mound in the trough I51high enough to prevent further flow of particles through the notches I62in the gate I59. The particles piling up behind the gate I59 will chokeoff flow of particles out of the aperture I5I and thus the completedrainage from the chute 265 of particles on the chute is prevented. Thesame action occurs with respect to the roll 24a and the chute 26a(Figure 4). Further, since the chute 26a is fed by the pipes 2I3, whilethe drainage of; particles off of the chute onto the roll is stopped,particles will be continued to be fed to thec-hute by the pipes 2 I3 butonly until the particlesjrise so as to choke the lower ends of thepipes. It will be noted that the lower ends of the pipes 2I3 are closeto the receiving surface H59. Further," when the recep tacle 2M fillshigh enough to cover the outlet of the hopper 2 I6, the flowfrom thehopper will also be choked off. Flow into the hopper will be stopped bythe maximum level device 226. Thus undesired flow of particles anywhereabove a stopped roll is effectively stopped.

The rolls below a stopped roll may continue to rotate and any materialleft in the chutes associated with these rolls will be treated andseparated into tails, heads, and backs in the manner hereinbeforedescribed.

From the foregoing it will be apparent to those skilled in the artthat'the illustrated embodiment thereof, and that accordingly, thedisclosure hereinvention may be variously changed and modified, orfeatures thereof, singly or collectively, embodied in other combinationsthan those illustrated, without departing from the spirit of myinvention, or sacrificing all of the advantages viding wall means beingso constructed and arranged that its upper margin is movable in adirection transversely of said margin while leaving said receptaclemeans in a fixed position; means for supporting said receptacle means;and said supporting means and said receptacle means being relatively soconstructed and arranged that said receptacle means is detachable fromsaid supporting means while leaving said dividing wall means inoperative position.-

. the longer general axis of said oblong cross-sec- 2. In apparatus forelectrostatic separation of material particles: receiving means having ametallic surface for receiving particles to be treated; and an elongatedmetallic electrode the longitudinal axis of which extends approximatelyparallel to said surface, said electrode having a substantially uniformcross-section of rounded oblong form, said electrode being so disposedthat tion extends in a general direction transverse to the nearestportion of said surface.

3. In apparatus for electrostatic separation of material particles:receiving means having a metallic surface for. receiving particles to betreated; and an elongated metallic electrode the longitudinal axis ofwhich extends approximately parallel to said surface; metallic dividingwall means disposed below and transverse to the general common plane ofsaid electrode and said receiving means; said electrode having asubstantially uniform cross-section of rounded oblong form, saidelectrode being so disposed that the longer general axis of said oblongcross-section extends in a general direction transverse to the nearestportion of said surface, and transverse to the general plane of saiddividing wall means.

4. In apparatus for electrostatic separationof material particles:receiving means having a metallic surface for receiving particles to betreated; and an elongated metallic electrode the longitudinal axis ofwhich extends approximately parallel to said surface, said electrodehaving a substantially uniform cross-section of generally ovoid form,said electrode being so disposed that the taper of said ovoidcross-section is toward said surface.

5. In apparatus for electrostatic separation of material particles:receiving means having a metallic surface for receiving particles to betreated;

and an elongated metallic electrode the longitrode;

and the general plane of said dividing wall means is approximatelytransverse to a lateral surface of said electrode.

' 6.' In combination in apparatus for electrostatic separation ofmaterial particles: means for treating the particles, including a roll,chute said roll-heating means; means responsive to the temperature ofthe particles on said chute means; and means, controlled by said lastnamed temperature responsive means, constructed and arranged to regulatethe heat supplied by said heating means for said chute means.

'7. In combination in apparatus for electrostatic separation of materialparticles: a cylindrical roll for receiving particles to be separated;inclined chute means for conveying particles to said roll, said chutemeans having a substantially rectilinear discharge edge; means forsupporting said-chute means with its discharge edge adjacent said roll;and means, for adjusting said chute means, so constructed and arrangedthat said chute means may be tilted, about an axis transverse to saidroll, from one plane into anzother plane at an angle to said first namedplane,

and so that said chute means is movable in its own general plane aboutan axis transverse to that plane.

8. In combination in apparatus for electrostatic separation of materialparticles: a hollow rotatable metallic roll for receiving particlesthereon; bearings in which end portions of said roll are journaled; agenerally cylindrical electrical heating unit disposed co-axially withand in said rolland rotatable with said roll; insulated contactmeanscarried by and rotatable with said roll at its respective ends;means connecting said roll-carried contacts to said heating, unit, saidroll and said heating unit being so constructed and arranged that uponremoval of said insulated roll-carried contact, means said heating unitis removable from andinsertable. into said hollow rollwhile said rollremains insaid bearings; and

relatively stationary means engaging said rollcarried contacts.

9. In combination in apparatus for electrostatic separation of materialparticles: means for receiving particles to be treated; an electrode forelectrostatically treating particles on said receiving means; metalliccombined housing means and receptacle means, so constructed and arrangedthat it shields said electrode from extraneous influences and receivesparticles coming from said receiving means; means, including pivotmeans, constructed and arranged to support said combined housing andreceptacle means in operative relation with respect to said elecsaidcombined housing and receptacle means and said supporting means being.relatively so constructed and arranged that by swinging said combinedhousing and receptacle means about said pivot means to a predeterminedposition said combined housing and receptacle means is removable fromsaid supporting means by predetermined movement of said combined housin2,218,510 and receptacle means relative to said supporting matelyparallel to said roll, constructed and arranged to charge said roll andparticles thereon bydnduction; metallic dividing wall means, the

upper margin of which is disposed below the level .of said electrode andspaced from said roll, so constructed and arranged that particlesprojected' ofi of said roll under the influence of electrostaticrepulsion by said roll and attraction by'said electrode may fall partlyto either side of said wall means depending on the speed of projection;said electrode being so constructed and arranged that mechanicaldeflection of particles by impingement against said electrode isdecreased. 7

11. In apparatus for electrostatic separation of material particles:receiving means having a metallic surface for receiving particles to betreated; and an elongated metallic electrode the longitudinal axis ofwhich extends approximately parallel to said surface; metallic dividingwall means disposed below and transverse to the general common plane ofsaid electrode and said receiving means and having its upper marginspaced from said surface at least as far as said electrode is spacedfrom said surface; said electrode having a cross-section of roundedoblong form, and being so disposed that the longer general axis of saidoblong cross-section extends in a general direction transverse to thenearest electrode is spaced from said surface; said electrode having across-section of generally ovoid form, said electrode being so disposedthat the taper of saidovoid cross-section is toward said surface, andthe general plane of said dividing wall means is approximatelytransverse to. a lateral surface of said electrode.

13. In combination in apparatus for electrostatic separation of materialparticles: a plurality of rolls, each roll being disposed atasuccessively lower level; chute means for feeding particles onto thehighest of said rolls; chute means, each for feeding material comingfrom a roll to the next lower roll; each of said chute means and therespective next lower roll being relatively so constructed and arrangedthat stoppage of said roll stops feeding of particles from said chutemeans to said roll; said first named chute means having a conveyingsurface leading from a receiving portion to a discharge portion anddisposed at an angle greater than the angle of WV repose of saidparticles; conduit means for feeding particles onto said receivingportion, said conduit means having a discharge aperture a predetermineddistance above said receiving portion; means, including confining wallmeans forming a confined space at the open side of said chute .means, soconstructed and arranged that if discharge of particles from said chutemeans ceases, feeding of particles to said chute means from saidconduitmeans to said-receiving portion may continue only until particlesin said confined space reach substantially the level of the dischargeaperture of said conduit means;

' means for applying power to rotate the lowermost of said rolls; andmeans whereby each other roll is driven by power transmitted to it froma lower roll.

14. In apparatus for electrostatic separation of material particles:chute means for conveying particles to a treating zone, said chutemeanscomprising an inclined plane portion having a first area of givenaverage leveland a second area of lower average level, said second areabeing narrower than said first area, said chute means being soconstructed and arranged that having a plurality of spaced apertures,disposed on said second area, so constructed and arranged as tocooperate with particles descending on said plane portion to distributethe particles substantially uniformly on said chute means by reason oftheir descent by gravityon said chute means.

15. In combination in apparatus for electrostatic separation of materialparticles: means for treating the particles, including means forconveying the particles into a treating zone, an electrode for producingan electrostatic field between said electrode and said conveying means,and heating means for heating said conveying means thereby to heat theparticles; means, dis-- posed in the path' of particles falling fromsaid conveying means out of said field, responsive to the temperature ofsaid falling particles; and

means, controlled by said temperature responsive means, constructed andarranged to regulate the heat supplied by said heating means.

16. In apparatus for electrostatic separation of material particles:chute means for conveying particles to a treating zone,v said chutemeans including a first conveying plane surface portion inclineddownwardly to a second conveying plane surface portion, said secondportion being inclined downwardly; in the "same general direction assaid first portion, and leading to the discharge edge of said chutemeans, said first portion making a predetermined angle with thehorizontal, greater than the angle'of repose of;

said particles, and said second portion making an angle with thehorizontal greater than said predetermined angle; a roll disposed withits axis substantially parallel to the discharge edge of said chutemeans and with an upper surface of said roll in proximity to saiddischarge edge;

and a barrier at the'discharge edge of said chute means, said barrierhaving a plurality of spaced apertures through which the particles aredischarged directly onto said surface of said roll.

EDWIN L. WIEGAND.

